21421431423 has 16 divisors (see below), whose sum is σ = 36269090560. Its totient is φ = 12240817848.

The previous prime is 21421431413. The next prime is 21421431433. The reversal of 21421431423 is 32413412412.

21421431423 is a `hidden beast` number, since 21 + 4 + 214 + 3 + 1 + 423 = 666.

It is an interprime number because it is at equal distance from previous prime (21421431413) and next prime (21421431433).

It is not a de Polignac number, because 21421431423 - 2¹² = 21421427327 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421431413) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56670265 + ... + 56670642.

It is an arithmetic number, because the mean of its divisors is an integer number (2266818160).

Almost surely, 2^21421431423 is an apocalyptic number.

21421431423 is a deficient number, since it is larger than the sum of its proper divisors (14847659137).

21421431423 is a wasteful number, since it uses less digits than its factorization.

21421431423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113340923 (or 113340917 counting only the distinct ones).

The product of its digits is 4608, while the sum is 27.

Adding to 21421431423 its reverse (32413412412), we get a palindrome (53834843835).

The spelling of 21421431423 in words is "twenty-one billion, four hundred twenty-one million, four hundred thirty-one thousand, four hundred twenty-three".